The most persistent and intractable cause of infant and child mortality and morbidity in the US remains preterm and low birthweight deliveries. Pregnant women in the US experience the highest incidence of these complications among developed countries. Despite many efforts at increasing prenatal care, rates of preterm delivery have not substantially changed in the last decade. Even more disturbing is the observation that immigrant Hispanic women experience worsening birth outcomes the longer they live in the US, despite increasing access to prenatal care, improved socio-economic status and better education. (Within five years after moving to the US, the odds ratio for preterm low birth weight delivery increases by 1.9, from 4% to 7%.)